Debouzie Domitien, Heizmann Annie, Desouhant Emmanuel, Menu Frédéric
UMR CNRS 5558 Biométrie, Génétique et Biologie des Populations, Université Claude Bernard, 43, bd du 11 novembre 1918, F-69622, Villeurbanne Cedex, (France).
Oecologia. 1996 Oct;108(1):151-158. doi: 10.1007/BF00333226.
Detection of interspecific competition between insects is often sensitive to scaling. We give an example of scale-dependent interference between the weevil Curculio elephas and the moth Cydia splendana, which both have larvae that develop in the fruits of chestnut Castanea sativa. Measures at three scales were considered: chestnut, husk (with one to three fertile fruits) and tree. Data come from observations in the field over 14 years, complemented by experiments done directly in trees. Data on individual chestnut fruits revealed a marked statistical interference between the two insects. Experiments demonstrated that presence of a moth larva in a fruit usually inhibits weevil egg-laying. Conversely, weevil presence does not strongly modify moth larval behavior. Cases of double infestation often correspond to fruits first attacked by the weevil. With measures on husks, interference between the two insects was observed only in some trees; its intensity was always weaker than in the chestnuts themselves. At the scale of entire trees, rates of infestation by each insect are not correlated. Interference in chestnut fruits is interpreted by assuming that the weevil female either is sensitive to a repellent molecule originating from a moth larva or its frass, or can detect moth larval sounds. Mechanisms governing infestation rates from data per tree are discussed in relation to those found at fruit scale and to plant-insect interactions. The need to estimate available resources both from quantitative and qualitative points of view is emphasized.
昆虫种间竞争的检测往往对尺度很敏感。我们给出了一个象鼻虫Curculio elephas和蛾类Cydia splendana之间尺度依赖性干扰的例子，这两种昆虫的幼虫都在欧洲栗Castanea sativa的果实中发育。我们考虑了三个尺度的测量：栗树、果壳（带有一到三个可育果实）和整棵树。数据来自14年的野外观察，并辅以直接在树上进行的实验。关于单个栗实的数据显示这两种昆虫之间存在显著的统计学干扰。实验表明，果实中蛾幼虫的存在通常会抑制象鼻虫产卵。相反，象鼻虫的存在并不会强烈改变蛾幼虫的行为。双重侵染的情况通常对应于首先受到象鼻虫攻击的果实。在果壳尺度上，仅在部分树木中观察到这两种昆虫之间的干扰；其强度总是弱于栗实本身。在整棵树的尺度上，每种昆虫的侵染率没有相关性。通过假设象鼻虫雌虫要么对象源于蛾幼虫或其粪便的驱避分子敏感，要么能检测到蛾幼虫的声音，来解释栗实中的干扰现象。结合在果实尺度上发现的情况以及植物 - 昆虫相互作用，讨论了从每棵树的数据中得出的侵染率控制机制。强调了从数量和质量角度估计可用资源的必要性。
